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Driving Impressions
When it comes to trucks, numbers matter, arguably more than they do with cars. The most popular engine for the GMC Yukon is the 5.3-liter V8, which produces 320 horsepower and 340 pound-feet of torque. Our test Yukon was listed at 5677 pounds.
Examining these numbers should give a good idea of how a 5.3-liter Yukon will perform against the competition. By comparison, the 2008 Ford Expedition puts up a 5.4-liter V8 making 300 hp and 365 lb.-ft. of torque with a six-speed automatic and tips the scales at 5805 pounds. The 2008 Nissan Armada's 5.6-liter V8 makes 317 hp and 385 lb.-ft. of torque, mates to a five-speed automatic and carries a curb weight of 5593 pounds. Toyota's redesigned 2008 Sequoia is offered with a 5.7-liter V8 making 381 hp and 401 lb.-ft. of torque with a six-speed automatic and weighs 5730 pounds.
Note, however, that the Yukon's 5.3-liter engine comes with a four-speed automatic transmission, while many full-size SUVs now come with five-, six-, and seven-speed automatics. More gears generally means smoother operation, better fuel economy, quicker acceleration performance or all three. The Yukon's four-speed automatic negates any power advantage the Yukon might otherwise have enjoyed at least as far as outright acceleration is concerned. Put another way, while it'll easily hold its own on the interstates, the Yukon isn't going to win many stoplight races.
Not so, though, the Yukon Denali, which would leave its lesser sibling and most of the others in the dust were its driver so inclined. The Denali packs a 380-hp 6.2-liter V8 and six-speed automatic. It delivers willing power at any speed and makes the Denali feel like a much lighter vehicle.
Fuel economy is a much better story for the Yukon. EPA fuel economy numbers range from 14 mpg city and 19 highway for the 4.8 2WD and 5.3 4WD models to 14/20 for the 5.3 2WD to 12/18 for the AWD Denali with the 6.2 V8. The Yukon's Active Fuel Management system, which shuts down half of the engine's cylinders under light load helps the 2008 Yukon best the Expedition and Armada and run neck and neck with the new Sequoia.
In towing, the Yukon's 8200-pound rating trails all the competitors. Ford and Nissan rate their entries at a maximum of 9100 pounds, and the new Sequoia can tow up to 10,000 pounds. On the other hand, GM tends to be more conservative than other manufacturers with its tow ratings. Tow ratings have almost as much to do with lawyers and marketing professionals as they have to do with engineers.
Driving a Yukon is pleasant. Power comes on smoothly, with no surges or hiccups, and it is accompanied by a pleasant tone that reminds us of classic dual exhaust. Transitions effected by the fuel-management system are invisible, with the only indication a telltale in the information display in the tachometer. The four-speed automatic selects gears with little fanfare. The six-speed automatic in the Yukon Denali is even smoother; it also has a manual shift function managed by a rocker switch in the handgrip on the column shift lever.
We found the new two-mode hybrid system worked seamlessly. The system uses two electric motors in GM's new Electrically Variable Transmission (EVT) that has four fixed gears. The EVT is mated to a 6.0-liter version of the 6.2-liter V8 that also has Active Fuel Management. Total output is 332 horsepower and 367 pound-feet of torque. One of the motors aids power at low speeds and the other lends a hand at highway speeds. With just a little throttle, the electric motor can propel the Yukon up to 30 mph. Get on it a little harder, and the gasoline engine kicks in just as smoothly as in any Toyota hybrid. Like other systems, the gasoline engine turns off at stoplights and restarts as soon as it's needed.
The better news is Hybrid fuel economy. With 2WD, the Yukon Hybrid is rated at 21 mpg in the city and 22 on the highway. With 4WD, those numbers are 20 city/20 highway. The 2WD
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